The present invention relates to a driving scheme, and more particularly, to a driving circuit and a related method for calibrating an impedance of a load unit in the driving circuit.
Generally speaking, an interface standard for high-speed transmission, e.g. a driving circuit for outputting differential signals to drive a following stage, specifies an acceptable range for an impedance of a load unit in the driving circuit. When the driving circuit is used, it is necessary for designers to make the impedance fall within the acceptable range, to ensure the driving circuit operates correctly. In practical terms, however, the impedance of the resistance element usually varies from the acceptable range due to variation caused by process and environmental factors. Accordingly, the load unit is often implemented by adjustable resistance element(s), and a calibration scheme used for adjusting the impedance of the load unit is required.